#2 photo: same as above with -1 EV compensation, much better, some highlight on the bird is still blown.

These are quick and dirty experiements, so appologize to those of you who are purists

and just for kick, I swapped out the Kenko for the Canon 1.4X III. AF is a bit sluggist and the lens makes a grinding noise. I put the combo on my 1DX and the same noise persists. My hummingbirs were not cooperating, so I went out and shot an Amerian Kestrel instead. The IQ is fantastic, but I guess we know that already. So, if Canon can fix the AF issue with firmware, this is in fact a viable option.

Thanks for availing the results of your experiment, Lnguyen1203, that's really helpful. But just to be clear, the Canon 1.4X III only fits/works on the 70-300L throughout the latter part of the zoom range, right? Zoom it in too far and glass meets glass--ouch--right?

Thanks for availing the results of your experiment, Lnguyen1203, that's really helpful. But just to be clear, the Canon 1.4X III only fits/works on the 70-300L throughout the latter part of the zoom range, right? Zoom it in to far and glass meets glass--ouch--right?

My series of shots, ending up a 100% crop of a shot at 420mm are on the third page of that thread - think the link above should take you to that page.

That thread was started talking about the problems with the Kenko and some lenses on the 5DMkIII - turns out the problem is solved by turning AFMA off. The 70-300L was one of the lenses I didn't have a problem with

I am seriously thinking about getting one of the Kenko tele's, but has anyone had any experience using the 2X tele's with this lens?

D

I wouldn't if I were you. The 2X would rob you 2f stops and now you will ha f11 as the largest aperture. Meaning you can't use AF. Also, the 2X should be reserved for the very best, sharpest telephotos. If you need more reach, the Kenko 1.4x is OK.

I am seriously thinking about getting one of the Kenko tele's, but has anyone had any experience using the 2X tele's with this lens?

The 2x will most likely be worse than cropping, so it'd be only an advantage for very high iso shots - imho the 1.4x is the max for the 70-300L that makes any sense, not only because of the f11 problem.

This is a lens which has impressed me more and more I use one. On paper, it's a sharp but over priced lens. But in real world use, it's a fantastic performer. My only gripe is the lack of a tripod collar and it's low magnification at closer focus distances. Other than that, it's superb. It's also a lens which came in for some really harsh objections when it was first launched. Sure it was expensive, considering most 70-300 lenses were consumer grade zooms. This lens was cut from different cloth, it's a profressional lens and a pretty goon one too. Now it's a few years after it's launch, it's new price has come way down to a far more realistic level. It's still not a cheap lens per-say, but it's good value considering it's strong performance. It's relatively small, light and it's a great range to have. Personally, I'm holding out for a new 100-400 instead....which is going to be over priced and heavily maligned in the various forums on it's launch....but after a year....it'll come down in price somewhat.